Cochlear Implants Abstract: When a person loses hearing, cochlear implants make it possible to restore their ability to hear. Through surgical procedure, a system of electronic components is able to replace a damaged biological system. The most important part of the system is the electrical to biological connection made by the electrodes. Presented by: Connor Abens EE 4611 Kevin Chan May 2, 2014

Outline History of Cochlear Implant How the ear works Device structure Bio-friendly materials Pros/Cons Potential Improvements Future of Implant Kevin

History 1800 Allesandro Volta stimulated inner ear with electricity 1956 Cochlear implant was designed 1978 First multi-channel cochlear implant 1980 FDA began regulation of cochlear implants 1984 First implant in an adult approved by FDA 1990 FDA approved implant for children above 2 years old 2000 FDA approved implant for infants above 12 months of age. Connor

Development Cochlear Limited Advanced Bionics Cochlear™ Nucleus® This is the timeline of their implant components Advanced Bionics Harmony™ processor HiRes 90K™ implant Medical Electronics (MED-EL) MAESTRO™ 3.0 system

How the ear works Outer Canal Drum Middle (bones) Malleus, Incus, Stapes Inner Cochlea Auditory Nerve Kevin/Connor

Types of Hearing Loss Conductive Middle ear Sensorineural Inner ear stereocilia Cochlear Nerve Connection to brain Kevin

Components External Microphone Speech processor Transmitter Internal Receiver/Stimulator Electrode Array Kevin

MED-EL Electrode Array

Insertion of Electrode Array

Demonstrations of sound Robotic-like Fuzzy radio Context helps understanding http://auditoryneuroscience.com/prosthetics/noise_vocoded_speech Connor

Bio-friendly materials Silicone (1,5) Used to case the electronic Ceramics (older models) Weak and sensitive to external forces Titanium (2) Replaced ceramic components Platinum (3) Used for electrode contacts Kevin

Pros Cons Hearing is possible immediately after surgery Sensitivity to a variety of sounds Eliminates the reliance upon other people Potentially enjoy music Upgradable components Speech understanding without lip-reading Loss of natural hearing Possible negative side effects Must avoid water damage Electromagnetic noise Relative Volume isn’t automatic Static electricity damage Costs $45,000 to $105,000 Connor

Potential Improvements Completely internal Water resistivity Resolution Battery Life Manufacturing cost Biomaterials Connor

Laser-based cochlear implant Electric stimulation isn’t precise Modified cells react to light stimulation Precision lasers instead of electrodes Testing in rats and toadfish Infrared light affects calcium ion flow This causes nerve cells to release neurotransmitters Connor

Summary How the ear works Device structure Potential Improvements Infrared light stimulation Kevin

Sources General Information http://www.medel.com/us/ https://wiki.engr.illinois.edu/download/attachments/48137228/ECE+415+Cochlear+Implant+Final.pdf http://www.asu.edu/clas/shs/cilab/documents/publications/2004dormanwilson.pdf http://www.nlm.nih.gov/medlineplus/ency/article/007203.htm https://www.nidcd.nih.gov/health/hearing/pages/coch.aspx http://www.asha.org/public/hearing/Cochlear-Implant-Frequently-Asked-Questions/ http://www.cdc.gov/ncbddd/hearingloss/types.html http://teamhearing.org/blogs/?tag=cochlear-implants Laser based implant http://www.popsci.com/technology/article/2012-04/how-it-works-artificial-hearing-device-made-lasers Biomaterials http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3199815/

5 Key Concepts Sounds travels through the ear canal then causes mechanical vibration which creates waves in the cochlear fluid. Those waves move the small hairs that stimulate the nerve cells. Cochlear implant directly stimulates nerve cells in the cochlea Electronic Components consist of: microphone, processor, transmitter, stimulator. Silicone, ceramics, titanium and platinum are the materials used and accepted by the body. Electrode stimulation isn’t precise because electric current can disperse into tissue. Laser stimulation is being studied to improve the precision of implants.